Observing the new moon from any geographical position in the world is a well known problem. When the Moon is very close to the Sun, it is even more challenging and sometimes impossible to view the Moon through the unaided eye. The Moon is visible from the earth mostly because of the scattered light from the Sun. When both the Sun and the new moon are at a low elevation, the atmosphere around the Sun becomes as bright as the new moon, thereby providing poor or no contrast for observing the new moon.
The unaided eye observations suffer from various sources of noise. First, the angular proximity of the Sun reduces the sensitivity of the human eye. Second, the important observations are normally carried out when the Sun/Moon system is close to the horizon. Optical wavelengths are greatly absorbed during horizontal propagation, especially at low altitude sites and in the presence of natural or artificial pollutants. Accordingly, it may not be possible to observe the Moon through the unaided eye during bad weather conditions such as in the presence of clouds.
Microwave imaging can be used to observe the Moon in the presence of such noises. For microwave imaging, it can be assumed that the Sun and the Moon are blackbody radiators with thermodynamic temperatures of 6000K and 200-250K respectively. According to the assumptions, the peak of Sun's emission is at a wavelength of about 0.55 micron, which corresponds to the color yellow at optical wavelengths. The peak of emission of a blackbody at 200-300K is in Infrared (IR) range, therefore the emissions of the new moon can be observed in the IR. However, when the Moon is observed through Earth's atmosphere, the IR radiations are subject to a considerable attenuation. This attenuation increases when the Moon is observed at a low elevation such as in case of the new moon.
Therefore, there is a need to observe the new moon in the radio wavelengths with greater accuracy when the new Moon is in close proximity to the Sun. In addition, there is a need to observe the new moon under circumstances such as bad weather and poor contrast of the Moon with respect to the Sun.
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